Power hacksaw



C. l. DUVALL POWER HACKSAW Oct. 3, 1939.

Filed May 12, 1938 3 Sheets-Sheet l i lu @if Oct. 3, 1939.

c. l. DuvALl. 2,175,111

POWER HACKSAW Filed May 12, 1958 I5 Sheets-Sheet 2 Oct. 3, 1939. c. DUVALL 2,175,111

POWER HACKSAW Filed May l2, 1938 3 Sheets-Sheet 3 l 6* /75 1/9 l l 7 C.: if ,i 9

l uva/ZZ www Patented Oct. 3, 1939 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to a power hacksaw or the like designed especially but not necessarily for cutting metals.

It is aimed to provide a structure having a minimum of castings for the mounting and support of the operating parts; a construction Wherein the saw will be automatically lifted incidental to return to initial position; a structure wherein the saw frame freely slides on roller means; a construction wherein the column which mounts the saw, may be adjusted relatively to the Work, and a construction facilitating attachment of the work rigidly with respect to the saw.

The more specific objects and advantages will become apparent from a consideration of the description following taken in connection with accompanying drawings illustrating an operative embodiment.

In said drawings:

Figure l is a plan View of the improved hacksaw apparatus;

Figure 2 is a side elevation of said apparatus;

Figure 3 is a vertical sectional view taken substantially on the plane of line 3 3 of Figure 2;

Figure 4 is a horizontal sectional View taken substantially on the plane of line 4-4 of Figure 2;

Figure 5 is a section taken substantially on the plane of line 5-5 of Figure 4;

Figure 6 is a vertical section particularly showing parts between the column and gear casing;

Figure 7 is a horizontal section taken on the plane of line 'EL-'I of Figure 6;

Figure 8 is a detail section taken on the line 8-8 of Figure 3;

Figure 9 is a horizontal section through a modied form, particularly showing a second form of base, and

Figure 10 is a fragmentary elevation of the parts of Figure 9.

Referring specifically to the drawings wherein like reference characters designate like or similar parts, a base is provided at IB, of any desired configuration, preferably being a metallic casting. Rising from said base I0 is another casting in the form of a column II, which is adjustably mounted on the base, so that the saw or operating parts may be disposed at different angles and positions relatively to the work. To this end, the column II has a plate I2 through which bolts I3 pass and which also are disposed in irregular slots I4 so that they may be moved, to vary the angularity of the column II and fasten the column II rigidity in the different positions.

Vertically slidable along the column II is a slide I5, preferably a casting. Said slide I5 has a dovetailed projection i5, intertted in a dovetailed groove or slot I'I of the column. Said slide I5 has four studs I8 extending therefrom on which rollers I9 are journaled and which rollers have their peripheries grooved of V-form as shown at 20.

A generally inverted U-shaped frame 2I is adapted to carry a hacksaw blade 22 removably, in any desired manner, such blade being secured at one end to a projection 23 on said frame and at the other end to a projection 24 on adjustable securing means 25 of any desired type. Said frame 2i is preferably a casting and integral therewith is a mounting rail 26 whose longitudinal edges are beveled from opposite sides so as to iit the grooves 28. In order to provide for the take up of wear from time to time, the stub shafts or studs I8 may have bushings 2l adjustably mounted thereon, and on which bushings the rollers I8 are directly mounted.

Journaled on the plate I5 is a shaft 28, at the forward end of which, a disk 29 is keyed. A pitman 38 is pivoted by a wrist pin 3l to said disk 29 and by a wrist pin 32, to the hacksaw frame 2| so that rotation of the disk 29 will through the medium of the pitman 30, reciprocate the hacksaw frame 2I and accordingly the hacksaw blade 22.

Extending rearwardly from the column is a rod 33 which is screwed to a boss 34 on said column, as shown. A platform 35 by means of straps 36 is pivoted on said rod 33. On the platform 35, a prime mover, usually an electric motor 31 is fastened, and the power from which is used to rotate shaft 2B and accordingly reciprocate the saw blade 22. On the shaft 38 of said motor,

a pulley 39 is keyed, over which a belt 40 passes and which also passes over a pulley 4I keyed on a shaft 42. Shaft 42 is journaled in the slide I5. Intermeshing gearing 44 drives the shaft 28 from the shaft 42 and the slide I5 is supplemented or formed so as to provide a gear casing 45 around said gearing 44. Since the motor 3l is pivoted at 36 on rod 33, it tends to swing downwardly and thus by gravity tension the belt 40, at all times.

The work adapted to be sawn is suggested at 46, located between a fixed jaw 41 on the base I E! and a movable jaw 48 slidable on said base and controlled through the actuation of a screw 49, threaded at 50 in a portion of the base I0. Such screw is swivelled as at 5I in the jaw 48 and it is adapted to be operated for instance by a lever 52 pivoted at 53 to said screw 49. Adjacent screw 49 is a screw 48 which is adjustable to keep the jaws parallel in holding work which is shorter than the jaws.

It will be realized that the member I5 to gether with the frame 2| and saw are freely slidable and that the blade 22, by gravity rests on the work 46 and lowers automatically through gravity, as cutting progresses.

The said slide I5 and all parts carried thereby may be lifted, when desired as a unit, through operation of a lever 54 pivoted at 55 on the column II. Fastened to said lever is a chain or flexible element 5S, as at 5l and which chain is also fastened as at 5S to the slide I5.

Means are provided whereby the saw frame 2l and accordingly the blade 22 will be lifted and held lifted during return to normal position, after a sawing stroke, to prevent the rapid dulling of the saw teeth as would be the case if the saw were pulled back with the full weight thereon. To this end a cam 59 is keyed on the end of shaft 28 adjacent the column II. Cam 59 engages the upper end of a slidable block 5I), normally disengaged from the column II and urged upwardly into contact with the periphery of cam 5B by a contractile coil spring ESI, fastened at G2 to the block and at 53 to the slide. Pivoted on the slide I5 as at @t is a dog 55, one end of which has bearing Contact against the block GQ, and the other end of which is normally disengaged with the column il, a contractile coil spring GT, normally urging the free end of the dog 55 upwardly. The surfaces engaged by block Sti and dog d5 operate against smooth edges rather than against small notches, which soon wear away and are unreliable. As a result of the construction described, the block 60 and dog 55 will not interfere with lowering of the slide I5 and connected parts nor will it interfere with the lifting of such parts through the lifting of the lever 55. However, when the shaft 28 is rotating, at the end of a sawing or work stroke of the blade 22, the lobe of cam 59 will depress the block 60, swinging the lever 65 on the pivot 54, and thus wedging the block 50 and free end ofv the lever into contact with adjacent parts of the column II. When thus wedged, block G being stationary, the cam 59 turning on the upper end thereof will cause the slide I5 and all parts connected therewith including the saw frame 2| and blade 22 to lift and while lifted reciprocate back to initial position and then lower for the succeeding work stroke of the saw, such movement being controlled through the contour of said cam 59 and of course when the saw is in position to start a sawing operation, springs 6I and S1 will have restored the bloclr` 6@ and dog 65 to normal or released positions.

A modified form of base I@ may be resorted to when desired and for instance as shown at Illa in Figures 9 and 10. Such base has a vertical portion 'I0 notched as at 'II to receive the work 12, which is held therein through the medium of a chain 'I3 anchored to the base ID as at "I4, and the upper end of which has a ring 'I5 co-acting with a clamping screw I6 screw threaded at 'II in the member 10. An operating handle I8 may be pivoted at I9 to said screw 16. This construction, it will be realized, will enable the saw to be taken to the work that may be too heavy or awkward to be brought to the saw.

Various additional changes may be resorted to provided they fall within the spirit and scope of the invention.

I claim as my invention:

1. Sawing apparatus of the class described having a column, a slide movable on said column, a saw frame slidably mounted by the slide, means operable to reciprocate the saw frame comprising a motor, means pivotally mounting the motor on the column, and an endless driving member extending from the motor as part of said means whereby gravity will cause the tensioning of the endless driving member.

2. Sawing apparatus of the class described having a column, a slide vertically movable on the column, a saw frame movably mounted on the slide means operable to reciprocate the saw frame, a cam operated by said means, means on the slide adapted to bind against the column through operation of the cam to thereupon form a xed abutment for the cam to cause lifting of the frame incidental to its return to starting position, said second mentioned means comprising a block normally disengaged with the column, spring means urging the bock into engagement with the cam, and a wedging member on the slide operated by the block under action of said cam to cause the block to bind against the column.

3. Sawing apparatus of the class described having a column, a slide vertically movable on the column, a saw frame movably mounted on the slide, means operable to reciprocate the saw frame, a cam operated by said means, means 0n the slide adapted to bind against the column through operation of the cam to thereupon form a fixed abutment for the cam to cause lifting of the frame incidental to its return to starting position, said second mentioned means comprising a block normally disengaged with the column, spring means urging the block into engagement with the cam, a wedging member on the slide operated by the block under action of said cam to cause the block to bind against the column, said wedging means comprising a lever pivoted to the slide, said lever being engaged with the block, and a contractile coil spring connected to the lever and to the slide.

CHESTER I. DUVALL. 

